MathDB
A simple problem with a simple idea

Source: Tournament of towns Spring 2018 A-level P5

March 10, 2020
patternlogic

Problem Statement

There are 100 houses in the street, divided into 50 pairs. In each pair houses are right across the street one from another. On the right side of the street the houses have even numbers, while the houses on the left side have odd numbers. On both sides of the street the numbers increase from the beginning to the end of the street, but are not necessarily consecutive (some numbers may be omitted). For each house on the right side of the street, the difference between its number and the number of the opposite house was computed, and it turned out that all these values were different. Let nn be the greatest number of a house on this street. Find the smallest possible value of nn. (8 points)
Maxim Didin